1. Technical Field
The present system relates generally to medical systems for use in diagnosis and treatment.
2. Background Description
In the context of the rapidly increasing cost of health care, the role of the primary care physician as a gatekeeper to the resources of the medical system is critical. The challenge in using health care resources in a cost-effective manner is especially acute in diagnosis and treatment of heart conditions and other conditions involving the evaluation of sounds and murmurs.
The evaluation of sounds has importance in the diagnosis of a variety of medical conditions affecting, cardiac, gastro-intestinal, pulmonary and other anatomical systems. As an illustration, in cardiac diagnosis, the heart is listened to using a stethoscope. The primary heart sounds with reference to the sys/diastolic phase of the heart are identified. It is then determined whether there are any abnormal heart sounds present, such as murmurs and/or clicks. The relative loudness, duration, intensity pattern, spectral quality and time sequence of the heart sounds are assessed. The heart sounds are interpreted in terms of the physiological model of the action of the heart muscle, valves and chambers. A hypothesis is then developed about any possible disease states based on the acoustic evidence and knowledge of the patient""s medical history. Possible diagnoses are differentiated by varying the placement of the microphone, the patient""s posture, or by having the patient execute different maneuvers that accentuate or diminish certain heart sounds. The accumulated evidence is evaluated for the presence of heart disease. It is then decided whether to refer the patient for diagnostic imaging, particularly ultrasound.
A description of some of the many disadvantages of conventional auscultation of the heart follows. This description exemplifies difficulties in auditory evaluation of anatomical features in general. Auscultation of the heart is a difficult task, for many reasons. The stethoscope itself transfers only a small fraction of the acoustic signal at the chest surface to the listener""s ears, and filters the cardiac acoustic signal in the process.
Much of the signal energy in many heart sounds is below the threshold of human hearing, and this situation only tends to worsen with increased age of the listener. Auscultation also relies on correctly determining the correspondence of the primary heart sounds with the systolic and diastolic phase of the heart, which is made more difficult when the systolic and diastolic intervals are more equal, typically at elevated heart rates. Auscultation also relies on detecting the correct sequence of brief events that are closely spaced in time, something that is difficult for human listeners.
Learning auscultation is also difficult because diagnostic instructional manuals rely on subjective descriptions of heart sounds, which require much practice to appreciate.
Furthermore, the practice and teaching of the clinical skill of auscultation of the heart has declined among physicians. Recent tests have demonstrated that physicians can identify reliably only a small number of standard heart sounds and murmurs, as described by Burdick et al., in xe2x80x9cPhysical Diagnosis Skills of Physicians in Training: A Focused Assessmentxe2x80x9d, Acad. Emerg. Med., 2(7), pp. 622-29, July 1995; Mangione et al., in xe2x80x9cCardiac Auscultatory Skills of Internal Medicine and Family Practice Trainees: A Comparison of Diagnostic Proficiencyxe2x80x9d, Journal of the American Medical Association, 278(9), pp. 717-22, September 1997; Gracely et al., in The Teaching and Practice of Cardiac Auscultation During Internal Medicine and Cardiology Training: A Nationwide Surveyxe2x80x9d, Annals of Internal Medicine, 119(1), pp. 47-54, July 1997. Consequently, serious heart murmurs in many patients go undetected by physicians.
Furthermore, the decline in auscultation skills has led to an over-reliance on echocardiography, resulting in a large number of unnecessary and expensive diagnostic studies. As a result, reimbursement for echocardiography has recently come under scrutiny by Medicare. The problems described for cardiac diagnosis involving sound evaluation similarly apply to, gastro-intestinal, pulmonary and other anatomical systems.
Accordingly, it is desirable and advantageous to derive a system to support diagnostic decision making involving sound evaluation for use in human and animal diagnosis.
A diagnostic decision support system provides diagnostic decision support for auditory evaluation of anatomical features and is applicable to virtually any living creature. The system processes an acoustic signal for medical applications by acquiring acoustic data representative of an acoustic signal associated with an anatomical function. The acquired acoustic data is stored in a file associated with a patient medical record. The acquired acoustic data and medical record information is automatically analyzed to determine physiologically significant features useful in medical diagnosis. Information is generated supporting medical diagnosis based on the automatic analysis.
In another feature of the invention the analysis of the acquired acoustic data may be partially automatic and involve User input of information for use in facilitating diagnostic decision making.
In a further feature, the system processes patient identification information and acoustic test type information (e.g. identifying anatomical function, anatomical condition, auditory test anatomical location or patient posture).